Boom construction



Dec.30, i947. e. 1.. TURNER r 2,433,584

BOOM CONSTRUCTION Filed Feb. 21, 1946 IN V EN TOR. qzgel Tzmwr Patented Dec. 30, 1947 UNITED STATES PATENT OFFICE $06M 'CCNS'IRiTC'IION George L; Turner, Battle Creek Mich, assignor to Clark Equipment company, Buchanan, Mich, a corporation of Michigan Application February 21, 1946, Serial No. 649,238

This invention relates to booin constructions, and more particularly i concerned with a constructionoi this type adapted to be installed on industrial material handling trucks or the fork type in order to convert them for operation as a crane. v

in many plants where such industrial forklift trucks are in use for the handling of material, it sometimes becomes necessary to provide for crane Or boom operations and, in such cases, the conventional type or truck is not adapted for such use The present invention contemplates simple and economical means for converting such a truck to use for boom operations in order to lift material and swing it into position for loading or unloading. The mechanism can be readily attached to a standard fork truck with a minimum of conversion changes, and can be readily dismantled therefrom when it is desired to use the truc again as a fork truck.

one of the object's crthe present invention is to broaden the utility or a fork lift truck by the attachment or the pr sent ihv'efltidii.

Another object of the present invention is to provide a detachable boom construction for such type or truck inwhich the boom will remain at right angles to the face plate of thelifting carridge when the uprights of the truck are tilted forwardly, but can be swung laterally when the uprights are tilted slightly rearwardl'y'.

The present invention will appear more fully irom the following detailed description which, taken in conjunction with the accompanying rawing, will disclose to those skilled in the art, the particular construction and operation of a preferred form of the present invention.

In the drawing: Figure 1 is a side View of a conventional ind'iisti'i'al truck provided with the attachment of the present invention; and I W Figure 2 is a, plan view of the truck shown in Figure 1. Referring now in detail to the drawing, there is disclosed anindustrial truck, indicated at 5, of the lift type having a front driving axle and drive wheels 6 by which the truck is propelled. The truckis provided with the usual type of steering column 1 and steering wheel 8 and, at the forward end thereof has mounted the upright structure, indicated generally at 9, which is pivotall-y secured for tilting movement about a horizontal axis adjacent its lower end.

This tilting movement is accomplished by means of pistons (not shown) which, through 6 Claims. (Cl. 214-113) the piston rods I0, are connected to brackets 12 secured on the outer side of each of the stationary vertical uprights l3. The uprights l3 adjacent their top are cross connected by the cross member I4, and preferably are of channel form 0011*- taining inner telescopically movable uprights I5 which project slightly above the cross member l4 and, which carry within the channel portions thereof a carriage member l6 including a face plate l1 upon which are mounted the lift fingers or forks iii. A truck of this type is generally shown in United States Patent No. 2,368,122, issued January 30, 1945,- to Elmer J Dunham, to which reference may be had for a more complete description of the upright structure and loadsupporting carriage;

There is provided on the lower face late I? intermediate the forks IS a bracket member [9 to which is hingedly connected a boom 20, which boom maybe a tubular member seated in the bracket the bracket being formed with an outwardly open socket in which the end 22 of the boom is seated for oscillating motion. Adjacent its outer end, the boom member 20 is provided with a ring 23 from which is suspended the cable 24 carrying the hook 25 for engagement with the load to be lifted. There is also provided a ring 26 on the top of the outer end of the boom to which is connected a cable 21, this cable entering a connector 28 at its opposite end from which two angularly extending cables 29 extend to anchor positions 30 on the movable uprights 15.

The load supporting carriage I6 is adapted to be raised or lowered within the uprights I5 by means of a chain connection thereto, the carriage having rollers guided within the channel portions of the uprights l5 and the chains being trained over sprockets carried by the upper end of a piston operating in the hydraulic cylinder 32. The arrangement is so constructed that the car riage l6, anchoring the lower end of the boom, moves at a rate double the rate of the movement of the telescopic uprights l5, anchoring the cables 29 and, as will be seen clearly from Figure 1, the boom itself remains substantially at the same inclination a it is moved upwardly. The rela tion of the length of cables 21 and 29 anchored to the movable uprights, to the boom length and the movement of the carriage it determines this angularity of the boom. Thus, in the structure disclosed, the boom maintains a substantially constant angularity with respect to the ground surface throughout the range of its vertical movement;

It will be apparent by reason of the tripod connection between the cables 2! and 29 that when the upright assembly 9 is tilted slightly forwardly, the boom will be held in a position extendin normal to the face plate [1, or in longitudinal alinement with the longitudinal center of the truck 5.

However, when theupright a assembly is tilted slightly to the rear, it is apparent that this condition reverses itself and the boom has a tendency to swing laterally and can be moved readily either to one side or the other side of the truck, the limited angularity of movement being indicated by the lines A and B of Figure 2. The tilting movement of the uprights is controlled by'the. operator through the piston and piston rod connections 10 so that the boom may be swung later- ,7 ally to pick up a load, and the uprights then tilted forwardly swinging the load into the longi-' tudinal center plan of the truck for transporting the load. It is possible with a truck of this type to control the tilting movement of the uprights as well as the lifting movement of the load carriage simultaneously so that very easy maneuverability of the boom can be attained,

The relationship of the relative lengths of the cables 21 and 29 will determine the amount of lateral swinging movement of the boom, 'as Well as the angle of tilt required in. the uprights to center the boom longitudinally of the truck or to allow it to be swung laterally. It is apparent that to detach the boom from the truck, .it is only necessary to remove the anchor connections 30, which may be of the pin and clevis type, or may be merely hooks carried by the cables 29 and hooking into rings or eyes carried by the upper ends of the uprights I5. When the cables 29 are thus detached, the boom may be lifted out of the socket l9, and is entirely free of the truck. To reassemble the boom to the truck, it is only necessary to place the lower end thereof in'the socket i9 and re-engage the cables 29 with theanchcrs 30. Thus, a very simple and readily detachable boom structure is provided. I A i It is therefore believed apparent that there is provided by the present inventiona siinplified means for broadening the utility of th-e conventional fork lift truck by providing a readily detachable boom structure which is capable of selfcentering itself in the longitudinal plane of the truck and can be swung laterally for either loading or unloading operations by control of the tiltable uprights. Furthermore, the, load carried by the boom can be raised or lowered readily due to its support in the movable load carriage of the truck to allow a load to be, picked up andtransported by the operator and discharged either'forwardly of the truck or laterally to either side thereof.

I am aware that changes may be made in certain details of the present invention, and I therefore do not intend to be limited except as defined by the scope and spirit of the appended claims.

I claim: I

1. Inan industrial truck having a telescoping vertical mast at one end thereof including fixed and telescopically mounted movable uprights capable of forward or rearward tilting movement as a unit, and a load supporting carriage adapted to be raised and lowered relative to said mast, said carriage having forwardly projecting lift fingers the combination of a socket member'carried by said carriage intermediate'said fingers, a boom having one end thereof universally'supported in said socket member, and having a depending load 4 engaging means at the free end thereof, and cable means connecting the free end of the boom to the upper ends of the movable uprights of said vertical mast, said carriage and movable uprights 5 being vertically movable at different rates of speed and said cable means being so arranged as to maintain said boom at a constant angle relative to the mast.

2; In' an industrial truck havinga telescopic vertical mast at one end thereof capable of for- ,ward or rearward tilting movement and having a load supporting carriage adapted to be raised and lowered relative to said mast, the combinationofa socket member carried by said carriage,

a boom having one end thereof supported in said socket member, and having a depending load engaging means at the free end thereof, and cable means connecting the free end of the boom to the movable uprights of said vertical mast, said cable means including angularly directed cables secured at corresponding ends thereof to said movable uprights and having a common terminal connection to a third cable connected to the free end of the boom, whereby forward tilting of said uprights causes said boom to assume a position at right angles to a vertical plane through said uprights and rearward tilting provides for lateral swinging movement of said boom in either direction.

3. The combination, with an industrial truck having a forwardly and rearwardly tiltable vertical mast including stationary uprights and movable telescoping uprights and a load supporting carriage mounted for vertical movement in the telescoping uprights, of a socket member carried centrally on the forward face of said carriage, a boom member having one end seated in said socket member and being provided with a load engaging member depending from the free end 40 thereof, and cable means connecting the free end of said boom to each of the upper ends of the movable set of uprights in such manner that said boom remains in the same relative angular position with respect to the ground during its ver- 5 tical travel upon raising of said carriage and vertical extension of said movable uprights, said cable means causing said boom to maintain a position at right angles to a vertical plane through said uprights upon forward tilting of said mast and providing for lateral swinging movement of said boom in either direction upon rearward tilting of said mast.

4. The combination, with an industrial truck having a tiltable telescopic vertical mast at one end thereof and a load supporting carriage vertically movable therein, of a bracket member mounted centrally on the face of said carriage, a boom member having one end universally supported therein, a depending load engaging means on the opposite end of said. boom, and cable means connecting said opposite end of said boom to the telescopic portion of said mast, said cable means comprising two angularly directed cables having end anchorage to said mast and a third cable having end anchorage to said boom, all of said cables having common connection intermediate said mast and the free end of said boom.

5. For use with an industrial truck having a tiltable vertical telescopic mast at one end there- 0 of, including laterally spaced extensible uprights,

and a load supporting carriage vertically movable in said mast and having laterally spaced forwardly projecting lift fingers,'a boom'mechanism including a boom pole rounded at one end,

a socket member secured on the face of said'car- 2,433,584 5 riage intermediate said fingers and having a re- REFERENCES CITED cess receiving and Seating the rounded end of The following references are of record in the said pole, a load engaging cable depending from file of this patent: the opposite end of said pole, and divergent cable means for supporting the free end of said pole UNITED STATES PATENTS from the upper ends of said uprights. Number Name t 6. The boom mechanism set forth in claim 5 1,131,513 Hodgman Mar. 9, 1915 wherein said cable means includes three cables, 1,566,827 Chilson Dec. 22, 1925 one connected at one end to the free end of said 1,837,486 Remde Dec. 22, 1931 boom pole, and the other two connected at one 39 1,907,934 Cummings et al. May 9, 1933 end to the respective upper ends of said extensi- 2,364,493 Ulinski Dec. 5, 1944 ble uprights, the free ends of said cables being 2,368,122 Dunham Jan. 3 0, 1945 joined together at a point forwardly of said mast FOREIGN PATENTS but rearwardly of the free end of said pole.

15 Number Country Date GEORGE L. TURNER. 748,739 France Apr. 25, 1933 

